Where can I find the schema (XSD) for a .csproj file?

The csproj files are in fact MSBuild files. The xsd for those can be found here:

%windir%\Microsoft.NET\Framework\[framework version]\Microsoft.Build.xsd

The csproj files are MSBuild files so you should use the schema for MSBuild which is in:

%VS2008%\Xml\Schemas\1033\MSBuild\Microsoft.Build.Core.xsd

I was able to find it in %VS2008%\Xml\Schemas\1033\MSBuild\Microsoft.Build.Core.xsd. The target namespace matches the project files' namespace, and the structure looks right.

The easiest way to figure this out is to unload that project in Visual Studio, then right-click and edit the csproj file.

1. Open the Visual Studio Solution
2. Unload one of the projects
3. Right-click on the unloaded project in the "Solution Explorer" pane
4. Click "Edit PROJECT_NAME.csproj"
5. Open the "Properties" pane in Visual Studio
6. Click anywhere inside the editor pane for the .csproj file
7. The "Properties" pane should update with different information
8. Look in the "Schemas" for a list of schemas that apply to that .csproj file

I tried this in Visual Studio 2013, but this should apply to multiple versions of Visual Studio, since at this point the .csproj file is treated like any other XML file.